The present invention relates to removable components that are included in mechanical, electrical, and electromechanical systems, and that are cooled by airflow or by flow of a liquid substance, and, in particular, to a removable component filler that can be substituted for a removable component when the removable component is removed from the system to ensure that the flow characteristics of cooling and/or liquid within the system are not deleteriously impacted by removal of the removable component.
It is increasingly common for mechanical, electromechanical, and electrical systems to be constructed from modular mechanical, electromechanical and electrical components. Modular components are easily interchanged for maintenance, for repair, and for enhancement made possible by new technologies and manufacturing methods embodied in, or applied to, one or more of the modular components that together compose a system. Modern computer systems and storage devices include large numbers of removable modular components, such as chips, printed circuit boards, disk drives, power supplies, and various peripheral devices and peripheral device controllers.
FIG. 1 shows a simple, abstract illustration of a disk array storage device. The disk array storage device 100 includes a housing 102 and a bank 104 of hard disk drives. Disk arrays have many additional components, including communications and power interconnects, logic circuits, memory, and firmware and/or software controllers that implement communications protocols and I/O request handling. These additional components are located within the housing 102, but are not explicitly shown in FIG. 1 because they are outside the scope of the present invention.
In many systems, particularly electrical and electromechanical systems, modular components may comprise various heat-generating subcomponents and may therefore produce significant amounts of heat during operation. The heat must often be actively dissipated from within a system to the environment surrounding the system so that the internal temperature of the system does not rise above a level at which operation of system components deteriorates or fails. In many systems, airflow is created by internal fans that draw air over the surface of components, exchanging heat from the components to the air stream, and push the heated air out of the system through vents. In other systems, fluids are passed over components or conducted through tubing surrounding components to provide similar heat exchange functionality, the heat taken up by the fluids released in external radiating devices.
FIG. 2 shows the disk array of FIG. 1 with two internal cooling fans. The cooling fans 202 and 204 draw air through an intake port 206 at the front of the disk array past the bank of hard disk drives 104 and exhaust the heated air through output ports 208 and 210 at the rear of the disk array. In order to design disk arrays in which hard disk drives are sufficiently cooled during operation of the disk array, disk array designers carefully consider and calculate the arrangement of hard disk drives within the disk array, the interspacings between the hard disk drives, the size of the intake port 206, the sizes of the output ports 208 and 210, and the airflow generation capacities of the electrical fans 202 and 204.
In many systems, modular components may be added to increase system capabilities and may be removed when the capabilities and capacities provided by the module components are not needed in the system, as well as removed for maintenance, repair, and upgrading. FIG. 3 shows the disk array illustrated in FIGS. 1 and 2 with one hard disk drive removed from the bank of disk drives. Removal of the hard disk drive creates an open slot 302. The open slot is, in this case, much larger in cross-sectional area with respect to the front of the enclosure than the total of the cross-sectional areas of the interspacings between the hard disk drives in a fully filled bank of disk drives, such as the bank of disk drives 104 in FIGS. 1 and 2. The large open slot introduced by removal of the hard disk drive creates a relatively large channel through which air drawn into the enclosure 102 by electrical fans (202 and 204 in FIG. 2) can pass, so that much of the air flow generated by the electrical fans will be diverted through the slot 302 rather than pass through the much tighter interspacings between hard disk drives. As a result of the diversion of the airflow, the careful considerations and calculations for air cooling of the hard disk drives within a fully filled bank of disk drives may be wholly inapplicable to a disk array from which a disk drive has been removed. In many cases, removal of a disk drive will result in inadequate cooling of many of the remaining disk drives that may, in turn, result in degradation or wholesale failure of operation of one or more disk drives or in physical damage to disk drives or other heat-sensitive components within the disk array.
There are a number of ways to approach the problem outlined above with reference to FIGS. 1-3. In one approach, cooling design engineers may attempt to anticipate the effects of removing one or more hard disk drives from a disk array and to provide sufficiently powerful fans and complex baffling mechanisms to ensure that adequate airflow is maintained around all hard disk drives within the disk array despite removal of one or more hard disk drives. Such sophisticated design work is expensive and may not provide reliable solutions in all cases, particularly for unanticipated patterns of hard disk drive removal. Such solutions also lead to expensive disk arrays that are difficult to manufacture and that may require increased levels of maintenance during their lifetimes.
FIG. 4 illustrates a second approach to alleviating the problem described with reference to FIGS. 1-3. In FIG. 4, a rectangular-block-like hard disk drive filler 402 is inserted into the open slot 302 resulting from removal of a hard disk drive from the bank of hard disk drives 104, the hard disk drive filler 402 shown partially inserted. The size and shape of the hard disk drive filler 402 approximates the size and shape of a hard disk drive so that, once the hard disk drive filler is fully inserted into the bank of disk drives 104, the airflow characteristics of the disk array will closely approximate the airflow of a disk array with a fully filled bank of disk drives.
The solution illustrated in FIG. 4 is commercially viable, but has certain disadvantages. The rectangular-block-like filler has six sides that together form a continuous surface in order to approximate the continuous surface of a hard disk drive. The hard disk drive filler cannot therefore be manufactured by cheap injection-molding processes from plastic materials, but needs to be manufactured by a blow-molding process, constructed from subcomponents, or machined from a block of suitable material. These alternative manufacturing methods are expensive in comparison to injection molding. Moreover, continuous-surface, six-sided fillers do not lend themselves to convenient stacking for storage and shipping and are rather heavy, both characteristics adding significant cost to the shipping costs required for providing hard disk drive fillers to customers.
In order to avoid the expense of continuous-surface, six-sided hard disk drive fillers, customers and disk array manufacturers have employed soft foam and rigid foam fillers, but such fillers generally prove to be inadequate. They are not durable, and may degrade rapidly during removal and replacement and may become deformed and otherwise deteriorate during use. Furthermore, such makeshift fillers generally do not conform to the close manufacturing tolerances of hard disk drives and disk arrays, so that the airflow around disk drives within a disk array may be sufficiently disturbed by the presence of a makeshift filler to cause undesirable heat retention within the disk array or components of the disk array.
For these reasons, users and manufacturers of disk arrays have sought a cost-effective but durable and economical hard disk drive filler to take the place of hard disk drives removed from banks of hard disk drives in disk drive arrays.
One embodiment of the present invention is a 5-sided, injection-molded, hard disk drive filler that provides airflow obstruction characteristics equivalent to those of hard disk drives. The 5-sided, injection-molded, hard disk drive filler is manufactured from fire-resistant polymers to include warning labels and alphanumeric identification. The 5-sided, injection-molded, hard disk drive filler is designed to be stackable, includes a molded handle to facilitate insertion and extraction, and includes hollow, wedge-shaped baffles to produce turbulent airflow across the hard disk drive filler.